Here are the answers to the questions:

1. What tool was used for pathway enrichment analysis?
The tool used for pathway enrichment analysis was DAVID, based on Gene Ontology and KEGG pathway databases.

2. Was a tool version number provided?
No, the authors did not provide a version number for the DAVID tool.

3. What gene set library was queried (eg: GO, KEGG, Reactome or other)?
The gene set libraries queried were Gene Ontology (GO) and KEGG pathway databases.

4. Was a background gene list defined for pathway enrichment analysis?
Not described. The authors mentioned that the categories of KEGG Pathways served as background databases, but it is unclear if a specific background gene list was defined.

5. What statistical test was used for enrichment analysis?
Not described. However, in the Results section, the authors mentioned that P values were calculated by Chi-square test, but this appears to be related to the distribution of breakpoints in gene element regions rather than pathway enrichment analysis.

6. Was false discovery rate correction used to control the number of false positives in the pathway enrichment analysis?
Not described. There is no mention of false discovery rate correction or any other method for controlling false positives in the pathway enrichment analysis.